Longitudinal guiding element for motor vehicle seat

ABSTRACT

The invention relates to a longitudinal guiding element for a motor vehicle seat, comprising two rail-type guide elements extending in the longitudinal direction of the seat, and a guiding device by which means one guide element can be displaced in the longitudinal direction of the seat in relation to the other guide element. According to the invention, a first sliding guide ( 3, 4 ) is formed by a guiding slide ( 3 ) provided on one rail ( 1 ) and a guiding pin ( 4 ) provided on the other rail ( 2 ), and the second sliding guide ( 5, 6 ) is formed by a guiding pin ( 5 ) provided on one rail ( 1 ) and a guiding slide ( 6 ) provided on the other rail ( 2 ). The two sliding guides are successively arranged in the longitudinal direction of the seat.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a National Phase Application of InternationalApplication Number PCT/DE2004/000688, filed on Mar. 30, 2004, whichclaims priority of German Patent Application 103 17 239.4, filed on Apr.10, 2003.

BACKGROUND

The invention relates to a longitudinal guiding element for a motorvehicle seat.

A longitudinal guiding element for a seat of this kind comprises twoguide elements extending in the longitudinal direction of the rail, anda guiding device by which the one guide element can be displacedrelative to the other guide element in the longitudinal direction of therail. By providing one of these two guide elements to hold an upholsterycarrier of a motor vehicle seat and connecting the other guide elementto the body floor of the motor vehicle it is possible to adjust theposition of the corresponding motor vehicle seat in the seatlongitudinal direction by moving the one guide element relative to theother guide element. By seat longitudinal direction is thereby meantthat direction along which extend the thighs of a vehicle occupantsitting in the normal seated position on the corresponding vehicle seat.

The said guiding device has two sliding guides mounted one behind theother in the seat longitudinal direction which are each formed by aguiding slide and a guiding pin guided in the relevant sliding guide.When the one guide element is displaced relative to the other guideelement in the seat longitudinal direction there follows a relativemovement of the guiding pin in the associated guiding slide. Thisrelative movement takes place independently of whether the guiding slideor the guiding pin is mounted on the guide part which is fixed on thebody. In each case one of these two functional groups is mounted on theguide element which is fixed on the body and the other is mounted on thelongitudinally displaceable guide element. With this type oflongitudinal guiding element for a seat there is the problem that in thecase of a small distance—compared to the overall length of the relevantguide element—between the two guide pins in the seat longitudinaldirection there is the risk of damage to the arrangement in the event ofstronger loads on the vehicle seat with corresponding torque.

The object of the invention is therefore to provide a longitudinalguiding element for a seat of the type mentioned at the beginning whichis characterised by increased stability in respect of torque stresses.

BRIEF DESCRIPTION

This object is achieved according to the invention in that the firstsliding guide is formed by a guiding slide provided on the one rail andby a guiding pin provided on the other rail whilst the second slidingguide is formed by a guiding pin provided on the one rail and by aguiding slide provided on the other rail.

Expressed in other words, a guiding slide of the first sliding guide anda guiding pin of the second sliding guide are mounted on one rail onebehind the other, seen in the longitudinal direction of the seat, whilsta guiding pin of the first sliding guide and a guiding slide of thesecond sliding guide are mounted one behind the other on the other rail.It is hereby achieved that the distance between the two guiding pinschanges when the two guide elements are displaced relative to each otherin the seat longitudinal direction. This enables in turn a design of theguiding device overall such that in those longitudinal positions of theseat where a particular stability is required in respect of externaltorques a particularly wide distance can be provided between the twoguiding pins in the seat longitudinal direction.

If the corresponding vehicle seat is a rear seat in the second or thirdrow of seats in a vehicle where a displacement in the seat longitudinaldirection always occurs to make it easier for passengers to get into thevehicle or if additional cargo space is to be provided in the boot ofthe vehicle then a particular stability is required for the arrangementwhen the guide elements are in a relative position in which thecorresponding vehicle seat is set up for receiving a vehicle passenger.If the guide elements are however in a relative position only to alloweasy entry into the vehicle or to provide additional cargo space thenclearly the stability requirements for the arrangement are lower. Theguiding slides and guiding pins are therefore to be arranged so that inthe first mentioned case there is a particularly wide distance betweenthe guiding pins in the seat longitudinal direction.

If for example the two guide elements are displaceable relative to eachother in the rail longitudinal direction between a first and a secondend position whereby the one end position corresponds to a position inwhich the corresponding vehicle seat is to serve to receive a vehicleoccupant and the other end position corresponds to a position in whichentry into the vehicle is to be made easier and/or additional cargospace is to be provided, and if these two end positions can be adjustedin that the two guiding slides of the guiding device each extend betweena front stop in the seat longitudinal direction and a rear stop in theseat longitudinal direction which limit the movement of the relevantguiding pin in the guiding slide then preferably in the one end positionof the two guide elements the guiding pin of the sliding guide at thefront in the rail longitudinal guide bears against the front stop of theassociated guiding slide whilst the guiding pin of the rear slidingguide in the rail longitudinal direction bears against the rear stop ofthe guiding slide. In this end position the widest possible distance isset between the two guiding pins which ensures a correspondingly strongstability. This end position of the guide elements consequentlycorresponds to a seat longitudinal position in which the correspondingvehicle seat serves to receive a vehicle occupant.

In the other end position of the two guide elements however the guidingpin of the front sliding guide in the rail longitudinal direction bearsagainst its rear stop whilst the guiding pin of the rear sliding guidein the rail longitudinal direction bears against the front stop. Thiscorresponds to the smallest possible distance between the two guidingpins so that here there is a lower stability in respect of torquestresses. In this end position of the two guide elements the vehicleseat is thereby preferably only set up to provide an enlarged cargospace or the like.

The two guide elements are preferably formed as seat side parts whichare arranged horizontally side by side across the longitudinal directionof the seat and thereby form an inner and outer guide element wherebypreferably the outer guide element is to be mounted fixed on the bodyand the inner guide element serves to receive the upholstery carrier.The said guide elements are preferably arranged in pairs on the twoouter longitudinal sides of a motor vehicle seat.

In order to lock the longitudinal guiding element of the seat in its twoend positions a locking device is provided which can be released by anunlocking lever in order to execute a longitudinal adjustment of theseat.

For a defined guide of the guiding pins in the associated sliding guidesthe guiding pins are supported in the relevant sliding guide on the oneside along the vertical axis perpendicular to the seat longitudinaldirection and on the other side along a first horizontal direction(horizontal cross direction) perpendicular to the seat longitudinaldirection. The latter is thereby possible in that the guiding pins eachengage through the relevant sliding guide and bear with a widened endsection against the edge of the associated sliding guide. On the otherhand the two guide elements can be supported against one another alongthe opposite horizontal direction.

In order to enable the described support of the individual elements ofthe guiding device against one another corresponding sliding areas areformed on the guiding slides.

According to a preferred embodiment of the invention the sliding areasare formed by a separate slider preferably made of plastics which isfixed on the relevant sliding guide. This slider preferably has twoopposing slide faces to support the relevant guiding pin along thevertical axis as well as two further opposing slide faces to support theguiding pin along a first horizontal direction and to support the guideelements against one another along the second opposite horizontaldirection transversely to the seat longitudinal direction.

The sliding regions of the slider preferably extend only over a part ofthe extension of the relevant guiding slide in the seat longitudinaldirection so that that end section of the guiding slide in which theassociated guiding pin is then housed when the seat longitudinal guideis located in an end position in which the corresponding vehicle seat isprovided to receive a vehicle occupant is not covered by the slidingregions of the plastics slider. In this end position the guiding pinwhich is preferably made of metal then directly bears against theguiding slide which is likewise preferably made of metal so that thearrangement has a corresponding stability, more particularly there is norisk of damage to the plastics slider in the event of severe stresses.For a secure positioning of the relevant guiding pin in the said endsection the latter preferably has suitably shaped support faces andtapers towards the end of the guiding slide.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become apparentfrom the following description of an embodiment given by way of examplewith reference to the drawings.

FIG. 1 a is a perspective view of a motor vehicle seat located in theuseful position with a backrest and a seat trough whose seatlongitudinal position can be adjusted by a longitudinal guiding element;

FIG. 1 b is the motor vehicle seat of FIG. 1 a without a seat trough;

FIG. 2 is a view of the motor vehicle seat of FIGS. 1 a and 1 b afteradjustment of the seat longitudinal position;

FIG. 3 a is an exploded view of the longitudinal guiding element for aseat from FIGS. 1 a and 1 b;

FIG. 3 b is a perspective view of a section of the longitudinal guidingelement for a seat from FIG. 3 a.

FIG. 1 a shows a motor vehicle seat which has a seat trough W to hold aseat cushion on which a vehicle occupant can sit, as well as a backrestR which serves to support the back of an occupant seated on the vehicleseat.

DETAILED DESCRIPTION

The seat trough W runs between two side parts 1 of the seat which eachextend in the seat longitudinal direction x on the two longitudinalsides of the seat trough W. By seat longitudinal direction x is therebymeant that direction along which extend the thighs of a person sittingin the normal position on the corresponding vehicle seat. The two seatside parts 1 are connected to one another through a cross bar Q whichhas fixing points B for fixing the seat trough W on the cross bar Q inthe region of the front end, see FIG. 1 b. This cross bar Q extendshorizontally along a direction y perpendicular to the seat longitudinaldirection x.

By the front end of the seat trough W is meant here—seen in the seatlongitudinal direction x—the end of the seat trough W at a distance fromthe backrest R. By rear end of the seat trough W is meant that end inthe region of which the backrest R protrudes upwards from the seatunderframe.

The two side parts 1 further define a bearing axis S on which the seattrough W is mounted in the region of its rear end. This extends along ahorizontal direction y perpendicular to the seat longitudinal directionx.

Furthermore the two seat side parts 1 extending in the seat longitudinaldirection x have in the region of their rear end an upwardly protrudingend section 10 which serve as a backrest support for the backrest R andto which the backrest R is connected for swivel movement. The backrestthereby extends in its useful position illustrated in FIG. 1 a in whichit can serve to support the back of a vehicle occupant, along a verticalaxis z substantially perpendicular to the seat longitudinal direction xas well as to the horizontal transverse axis y.

The two seat side parts 1 between which the seat trough W is housed areeach mounted displaceable in the seat longitudinal direction x in afurther outer side part 2 to be fitted fixed on the body floor, as willbe explained in detail below with reference to FIG. 1 b.

FIG. 1 b shows the vehicle seat of FIG. 1 a without seat trough W sothat it is possible to see the individual details of the guiding deviceby which the inner side parts 1 holding the seat trough W can bedisplaced in the seat longitudinal direction x relative to the outerside parts 2 which are to be mounted fixed on the body floor.

In FIGS. 1 a and 1 b the inner side parts 1 are thereby located relativeto the outer side parts 2 in a rear position which corresponds to auseful position of the motor vehicle seat. This means in this positionin which the vehicle seat can be locked by a locking lever 7 it issuitable to receive a vehicle occupant. By displacing the two inner sideparts 1 from the position shown in FIGS. 1 a and 1 b forwards in theseat longitudinal direction x the seat trough W and the backrest R areshifted forwards in unison with the inner side parts 1. This enablesadditional cargo space to be provided behind the vehicle seat which ismore particularly the rear seat of a motor vehicle. If the vehicle seatis a seat in the second row in a motor vehicle which has overall threerows of seats then by moving the seat trough W and backrest R forwardsit becomes easier for passengers to enter the area in the third row ofseats. The inner and outer side parts 1, 2 thus form guide elementswhich enable the seat trough W and backrest R to move in the seatlongitudinal direction x. The outer side parts 2 thereby overlap theinner side parts 1 by a turned upper end section 21.

According to FIG. 1 b the guiding device by which the inner side parts 1can be moved relative to the outer side parts 2 has in each pair of sideparts 1, 2 two sliding guides 3,4 and 5,6 arranged in succession in theseat longitudinal direction x and each consisting of a guiding slide 3,6 and a bolt 4, 5 guided in the relevant guiding slide 3,6. A specialfeature of the vehicle seat illustrated in FIG. 1 b thereby lies in thefact that in the case of the relevant front sliding guide 3, 4 in theseat longitudinal direction the guiding slide 3 is mounted on the innerside part 1 and the associated guiding pin in the form of a guide bolt 4is mounted on the outer side part 2, whilst the rear sliding guides 5, 6in the seat longitudinal direction are each formed by a guiding slide 6formed on the outer side part 2 and by a guide bolt 5 mounted on theinner side part 1.

This means that in the case of the rear sliding guide 5, 6, comparedwith the front sliding guides 3, 4 it is possible to interchange theassociation between the guide bolt and guiding slide and the inner andouter seat side part. This has the result that in the useful state ofthe vehicle seat illustrated in FIGS. 1 a and 1 b where the inner sideparts 1 are moved relative to the outer side parts 2 into their rearmostend position the front bolts 4 each bear against the front end of theassociated sliding guide 3 and in the case of the rear sliding guides 5,6 the bolts 5 each bear against the rear end of the associated slidingguide 6. The guide bolts 4, 5 mounted on each longitudinal side of thevehicle seat one behind the other in the seat longitudinal direction xthereby have a maximum spacing A in the seat longitudinal direction xwhich results in improved stability in the arrangement in respect oftorque stresses.

With a conventional guiding device where for example all the guide boltsare each attached to the inner side parts 1 and all the guiding slidesare attached to the outer side parts 2, the guide bolts would then inthe state of the vehicle seat illustrated in FIG. 1 b both each be atthe rear end of the associated guiding slide. The distance between theguide bolts along the seat longitudinal direction x would thereby beconsiderably shorter.

FIG. 2 shows the vehicle seat of FIGS. 1 a and 1 b after the maximumforward displacement of the inner side parts 1 in the seat longitudinaldirection (together with the relevant front guiding slide 3 and therelevant rear guide bolt 5). For this, locking levers 7 have previouslybeen unlocked by an unlocking rod 70 sprung in the locking device inorder to enable the inner side parts 1 to move forwards relative to theouter side parts 2.

It can be seen from FIG. 2 that in the forwardly adjusted state of theinner side parts 1 (and thus also of the seat trough W and the backrestR) the front guide bolts 4 each bear against the rear end of theassociated guiding slide 3 and the rear guide bolts 5 each bear againstthe front end of the associated guiding slide 6. Compared with theuseful position of the vehicle seat illustrated in FIGS. 1 a and 1 bthere is here a clearly shorter distance a between the front and rearguide bolts 4, 5 in the seat longitudinal direction x. This is howevernot a problem because the motor vehicle seat in the forwardly displacedseat position illustrated in FIG. 2 serves not to receive a vehicleoccupant but rather only to provide an enlarged stowage space behind thevehicle seat or to provide easy entry for the vehicle passenger behindthe vehicle seat.

As a result the guide bolts 4, 5 move up to each other when the innerside parts 1 are shifted forwards from the useful position, and moveaway from each other when the inner side parts 1 are pushed back againinto the useful position illustrated in FIGS. 1 a and 1 b.

In order to prevent the motor vehicle seat from being moved throughmisuse e.g. by a child sifting on the relevant seat, from the usefulposition illustrated in FIGS. 1 a and 1 b into the forwardly displacedposition illustrated in FIG. 2, according to a further development ofthe invention the unlocking lever (in the form of an unlocking rod 70)can only be accessible to a passenger when the backrest R has beenfolded forwards onto the seat trough W. The motor vehicle seat can inthis case only then be moved forward from its useful position when thebackrest R has been folded forwards onto the seat trough W to provideadditional cargo space. This preferred further development of theinvention is obviously only applicable in those vehicle seats where thebackrest can be folded forwards in the normal way onto the seat surface.

In order to completely rule out an occupant taking his place on thevehicle seat in the forwardly displaced position shown in FIG. 2 thebackrest which has been folded forwards onto the seat trough can belocked in the forwardly displaced position of the seat so that it canonly be unlocked and raised up again after it has moved back into itsuseful position (according to FIGS. 1 a and 1 b).

The construction of the relevant guiding device is shown in detailedform in FIGS. 3 a and 3 b using the example of an inner side part 1 andouter side part 2.

Each guiding device comprises a front sliding guide 3, 4 and a rearsliding guide 5, 6 whereby the front sliding guide 3, 4 consists of aguiding slide 3 formed on the inner side part 1 and of a guide bolt 4fixed at a fixing point 24 on the outer side part 2 and the relevantrear sliding guide 5, 6 consists of a guiding slide 6 formed on theouter side part 2 and a guide bolt 5 fixed on the inner side part 1.

The guide bolts 4, 5 have at one axial end a fixing section 41 and 51with which they are fixed on the associated side part 2 and 1respectively, and are provided at the other axial end each with a head45 or 55 by which they project out of the relevant guiding slides 3 and6. Between the fixing section 41, 51 and the relevant head 45 and 55extends a sliding section 40, 50 designed as a connecting section andwith which the relevant guide bolts 4, 5 can slide in the associatedguiding slides 3 and 6.

In order to facilitate the sliding movement of the guide bolts 4, 5 inthe relevant associated guiding slide 3, 6 between the front and rearends 31, 32 and 61, 62 a slider 8, 9 made of plastics and having acircumferential fixing frame 86, 96 is inserted in each guiding slide 3,6.

The sliding regions 80 and 90 of the relevant sliders 8, 9 respectivelycomprise on the one side slide faces 84, 94 opposite one another alongthe vertical axis z between which the guide bolts 4, 5 are guidedthrough their slide sections 40, 50 and on which they are supportedalong the vertical axis z. Furthermore the sliding regions 80, 90 of thesliders 8, 9 each have a sliding face 82, 91 which point away from therelevant guiding slide 3, 6 in the direction of the relevant other sidepart 2, 1. Each other side part 2, 1 slides on these slide faces 82, 91respectively as the inner side parts 1 slide along relative to the outerside parts 2.

Finally the fixing frames 86, 96 of the sliders 8, 9 each still form aslide face 85, 95 which point away from the relevant guiding slide 3, 4in the direction of the head 45, 55 of the relevant associated guidebolt 4, 5. The guide bolts 4, 5 are hereby supported on these slidefaces 85, 95 along the transverse axis y on the sliders 8, 9 eachopposite the direction along which each other side part 2, 1 issupported on the slide face 82, 91 provided for this on the relevantslider 8, 9 along the horizontal transverse axis y.

It can further be seen from FIGS. 3 a and 3 b that the front guidingslide 3 tapers in the region of its front end 31 and the rear guidingslide 6 tapers in the region of its rear end 92. Furthermore the slider8 associated with the front guiding slide 3 in the region of its frontend has no slide faces 84 for vertical support of the associated bolt 4and the slider 9 associated with the rear guiding slide 6 has in theregion of its rear end no slide face 94 serving for the vertical supportof the associated guide bolt 5 since the corresponding slide faces 84,94 each do not extend over the overall length of the associated guidingslide 3, 6.

This means that in the useful position of the vehicle seat shown inFIGS. 1 a and 1 b where the seat is provided for receiving the vehicleoccupant and where the front bolt 4 bears against the front end 31 ofthe associated guiding slide 3 and the rear bolt bears against the rearend 62 of the associated guiding slide 6, the guide bolts 4, 5 each bearwith their sliding sections 40, 50 directly against the inside wall 30and 60 of the relevant guiding slides 3, 6. This prevents strain on theplastics sliders 8, 9 from the increased weight of a vehicle seatoccupied by a passenger. The guide bolts 4, 5 each consisting of metaland the inside walls 60, 90 of the guiding slides 6, 9 likewiseconsisting of metal then act directly on one another.

In that the guiding slides 3, 6 each taper in their end sections notcovered by the slide faces (in the region of the front end 31 of thefront guiding slide 3 and in the region of the rear end 62 of the rearguiding slide 6) the smoothest possible transition without steps isprovided for the guide bolts 4,5 between the sliding regions 80, 90 andthe said end sections of the relevant guiding slides 3,6.

In a further development of the arrangement illustrated in FIGS. 1 a to3 b it can be proposed that the front and rear guiding slides 3, 6overlap one another in the region of their facing ends 32, 61 in theuseful position of the vehicle seat (see FIGS. 1 a and 1 b) in the seatlongitudinal direction x. This corresponds to an enlarged extension ofthe guiding slides 3, 6 in the seat longitudinal direction x and sets upa larger displacement path for the side parts 1, 2 relative to eachother in the seat longitudinal direction x. The risk of a collisionbetween the guide bolts 4,5 does not arise here since in the usefulposition of the motor vehicle seat where the guide slides 3, 6 wouldoverlap one another the front guide bolt 4 is mounted in the region ofthe front end 31 of the front guiding slide 3 and the rear guide bolt 5is mounted in the region of the rear end 62 of the rear guiding slide 6.The guide bolts 4,5 are thus located precisely against the ends 31, 62of the guiding slides 3, 6 remote from the

1. A longitudinal guiding element for a motor vehicle seat with twoguide elements extended in a seat longitudinal direction and a guidingdevice by which one guide element is displaced in the seat longitudinaldirection relative to the other guide element wherein the guiding devicecomprises two sliding guides mounted one behind the other in the seatlongitudinal direction and each have a guiding slide and a guiding pinguided in the guiding slide, wherein a first sliding guide of the twosliding guides is formed by a guiding slide provided on the one rail anda guiding pin provided on the other rail and that a second sliding guideof the two sliding guides is formed by a guiding pin provided on the onerail and a guiding slide provided on the other rail.
 2. The longitudinalguiding element for a seat according to claim 1, wherein the two guideelements are displaceable relative to each other in the seatlongitudinal direction between a first end position and a second endposition.
 3. The longitudinal guiding element for a seat according toclaim 2, wherein the first guiding slide and the second guiding slideeach extend between a front stop in the rail longitudinal direction anda rear stop in the rail longitudinal direction wherein the stopsrestrict movement of the guiding pins in the guiding slides.
 4. Thelongitudinal guiding element for a seat according to claim 3 wherein inone end position of the two guide elements the guiding pin of a frontsliding guide in the seat longitudinal direction bears against the frontstop of the guiding slide and the guiding pin of a rear sliding guide inthe seat longitudinal direction bears against the rear stop of theguiding slide.
 5. The longitudinal guiding element for a seat accordingto claim 4 wherein in the other end position of the two guide elementsthe guiding pin of the front sliding guide in the seat longitudinaldirection bears against the rear stop of the guiding slide and theguiding pin of the rear sliding guide in the seat longitudinal directionbears against the front stop of the guiding slide.
 6. The longitudinalguiding element for a seat according to claim 4 wherein the one endposition of the guide elements corresponds to a useful position of theseat in which this is provided for use by a vehicle passenger, and thatthe other end position of the guide elements corresponds to a displacedposition of the seat in which this is not provided to receive a vehicleoccupant.
 7. The longitudinal guiding element for a seat according toclaim 1, wherein one guide element is provided to receive an upholsterycarrier of a motor vehicle seat and the other guide element is providedfor fixing on a structural assembly fixed on a floor of the motorvehicle.
 8. The longitudinal guiding element for a seat according toclaim 1, wherein the two guide elements are mounted side by sidehorizontally across the seat longitudinal direction and form an innerguide element and an outer guide element.
 9. The longitudinal guidingelement for a seat according to claim 1, wherein the two guide elementsare arranged as a pair on each of the two longitudinal sides of a motorvehicle seat.
 10. The longitudinal guiding element for a seat accordingto claim 1, wherein a locking device is provided for locking the guidingdevice in at least one seat longitudinal position.
 11. The longitudinalguiding element for a seat according to claim 1, wherein each guidingpin is supported in an associated guiding slide along a vertical axisperpendicular to the seat longitudinal direction.
 12. The longitudinalguiding element for a seat according to claim 1, wherein each guidingpin is supported at an edge of an associated guiding slide along ahorizontal transverse direction perpendicular to the seat longitudinaldirection.
 13. The longitudinal guiding element for a seat according toclaim 1, wherein the two guide elements are supported against oneanother at an edge of each guiding slide along a horizontal transversedirection perpendicular to the seat longitudinal direction.
 14. Thelongitudinal guiding element for a seat according to claim 1, wherein ineach guiding slide there is a slider for supporting at least one of anassociated guiding pin and the other guide element.
 15. The longitudinalguiding element for a seat according to claim 14, wherein each sliderhas at least one support face for supporting the associated guiding pinin a vertical direction and at least one support face for supporting atleast one of the associated guiding pin and the other guide element in ahorizontal direction across the seat longitudinal direction.
 16. Thelongitudinal guiding element for a seat according to claim 15, whereinthe support faces enable a support in two oppositely aligned directionsalong the vertical axis and a support in two oppositely aligneddirections along the horizontal axis perpendicular to the seatlongitudinal direction.
 17. The longitudinal guiding element for a seataccording to one of claims 14 to 16, wherein the sliders are made ofplastics.
 18. The longitudinal guiding element for a seat according toclaim 14 wherein, each slider extends with at least one part of a slideregion in the seat longitudinal direction only over a part of anextension of an associated guiding slide.
 19. The longitudinal guidingelement for a seat according to claim 18, wherein the two guide elementsare displaceable relative to each other in the seat longitudinaldirection between a first end position and a second end position andwherein in an end position of the first and second end positions servingas the useful position of the two guide elements the guiding pins arenot supported on the associated sliders along the vertical axis.
 20. Thelongitudinal guiding element for a seat according to claim 19, whereinthe guiding pins in the first end position of the guide elements are notsupported on the associated sliders along the vertical axis.
 21. Thelongitudinal guiding element for a seat according to claim 19 whereineach guiding slide tapers in an end section which is free of a slideregion of an associated slider in order to provide a continuous smoothtransition between the slide region and the end section of the guidingslide.
 22. The longitudinal guiding element for a seat according toclaim 1, wherein the guide elements and the guiding pins are made ofmetal.
 23. A motor vehicle seat having a longitudinal guiding elementfor the seat comprising; two guide elements extended in a seatlongitudinal direction and a guiding device by which one guide elementis displaced in the seat longitudinal direction relative to the otherguide element wherein the guiding device comprises two sliding guidesmounted one behind the other in the seat longitudinal direction and eachhave a guiding slide and a guiding pin guided in the guiding slide,wherein a first sliding guide of the two sliding guides is formed by aguiding slide provided on the one rail and a guiding pin provided on theother rail and that a second sliding guide of the two sliding guides isformed by a guiding pin provided on the one rail and a guiding slideprovided on the other rail, and further comprising a backrest.
 24. Themotor vehicle seat according to claim 23, wherein the backrest isfoldable from at least one upright position in which it serves tosupport a back of a vehicle occupant forwards in a direction of a seatunderframe of the vehicle seat.
 25. The motor vehicle seat according toclaim 24 wherein a locking device is provided for locking the guidingdevice in at least one seat longitudinal position and wherein thelocking device is associated with an unlocking element and that theunlocking element is only accessible for unlocking the locking devicewhen the backrest is folded forwards.
 26. The motor vehicle seataccording to claim 24 or 25 wherein the two guide elements aredisplaceable relative to each other in the seat longitudinal directionbetween a first end position and a second end position, the firstguiding slide and the second guiding slide each extend between a frontstop in the rail longitudinal direction and a rear stop in the raillongitudinal direction wherein the stops restrict movement of theguiding pins in the guiding slides, in one end position of the two guideelements the guiding pin of a front sliding guide in the seatlongitudinal direction bears against the front stop of the guiding slideand the guiding pin of a rear sliding guide in the seat longitudinaldirection bears against the rear stop of the guiding slide, the one endposition of the guide elements corresponds to a useful position of theseat in which this is provided for use by a vehicle passenger, and thatthe other end position of the guide elements corresponds to a displacedposition of the seat in which this is not provided to receive a vehicleoccupant, and wherein the backrest is lockable in its forward-foldedposition and that the backrest can only then be released for raisingback up into its upright position when the longitudinal guiding elementof the seat is located in the useful position.